package utils

import (
	"archive/zip"
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strings"
)

// SystemInfo contains information about the user's computer.
var SystemInfo SysInfo = GetSysInfo()

// SysInfo holds information about the user's installation
type SysInfo struct {
	SteamDir    string
	HomeDir     string
	FlatpakDir  string
	SteamGameID string
	GameDir     string
	CompatDir   string
	BepinDir    string
	PluginDir   string
	ConfigDir   string
	TmpDir      string
}

// CheckErr checks for an error, prints if it happened
func CheckErr(e error) {
	if e != nil {
		log.Fatal(e)
	}
}

// PathExists checks if file or directory exists
func PathExists(path string) bool {
	if _, err := os.Stat(path); err == nil {
		return true
	} else if os.IsNotExist(err) {
		return false
	} else {
		log.Fatal(err)
		return false
	}
}

// GetSysInfo gathers information about the user's installation
func GetSysInfo() SysInfo {

	var steamDir string = "/.local/share/Steam"
	var homeDir string = os.Getenv("HOME")
	var flatpakDir string = "/.var/app/com.valvesoftware.Steam" + steamDir
	var steamGameID string = "632360"

	var gameDir string
	if os.Getenv("R2MOD_INSTALL_DIR") != "" {
		gameDir = os.Getenv("R2MOD_INSTALL_DIR")
	} else if PathExists(homeDir + flatpakDir + "/steamapps/common/Risk of Rain 2") {
		gameDir = homeDir + flatpakDir + "/steamapps/common/Risk of Rain 2"
	} else {
		gameDir = homeDir + steamDir + "/steamapps/common/Risk of Rain 2"
	}

	var compatDir string
	if PathExists(homeDir + flatpakDir + "/steamapps/compatdata/" + steamGameID) {
		compatDir = homeDir + flatpakDir + "/steamapps/compatdata/" + steamGameID
	} else {
		compatDir = homeDir + steamDir + "/steamapps/compatdata/" + steamGameID
	}

	SystemInfo := SysInfo{
		SteamDir:    "/.local/share/Steam",
		HomeDir:     os.Getenv("HOME"),
		FlatpakDir:  "/.var/app/com.valvesoftware.Steam/.local/share/Steam",
		SteamGameID: "632360",
		GameDir:     gameDir,
		CompatDir:   compatDir,
		BepinDir:    gameDir + "/BepInEx",
		ConfigDir:   gameDir + "/BepInEx/config",
		PluginDir:   gameDir + "/BepInEx/plugins",
		TmpDir:      "/tmp/r2mod-go",
	}

	if !PathExists(SystemInfo.TmpDir) {
		log.Println("temp directory does not exist; creating...")
		err := os.Mkdir(SystemInfo.TmpDir, 0755)
		CheckErr(err)
	}

	if !PathExists(SystemInfo.TmpDir + "/dl") {
		log.Println("temp dl directory does not exist; creating...")
		err := os.Mkdir(SystemInfo.TmpDir+"/dl", 0755)
		CheckErr(err)
	}

	// Setup log file
	if PathExists(SystemInfo.TmpDir + "/r2mod-go.log") {
		err := os.Remove(SystemInfo.TmpDir + "/r2mod-go.log")
		CheckErr(err)
	}

	logFile, err := os.OpenFile(SystemInfo.TmpDir+"/r2mod-go.log", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
	CheckErr(err)

	log.SetOutput(logFile)

	log.Println("System Information : ")
	log.Println("	gameDir:", SystemInfo.GameDir)
	log.Println("	compatDir:", SystemInfo.CompatDir)
	log.Println("	bepinDir:", SystemInfo.BepinDir)
	log.Println("	configDir:", SystemInfo.ConfigDir)
	log.Println("	pluginDir:", SystemInfo.PluginDir)
	log.Println("	tmpDir:", SystemInfo.TmpDir)

	return SystemInfo
}

// Unzip takes input src and dest, unzips file.
func Unzip(src string, dest string) ([]string, error) {
	var filenames []string

	r, err := zip.OpenReader(src)
	CheckErr(err)

	defer r.Close()

	for _, f := range r.File {
		fpath := filepath.Join(dest, f.Name)

		if !strings.HasPrefix(fpath, filepath.Clean(dest)+string(os.PathSeparator)) {
			return filenames, fmt.Errorf("%s: illegal file path", fpath)
		}

		filenames = append(filenames, fpath)

		if f.FileInfo().IsDir() {
			os.MkdirAll(fpath, os.ModePerm)
			continue
		}

		if err = os.MkdirAll(filepath.Dir(fpath), os.ModePerm); err != nil {
			return filenames, err
		}

		outFile, err := os.OpenFile(fpath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
		if err != nil {
			return filenames, err
		}

		rc, err := f.Open()
		if err != nil {
			return filenames, err
		}

		_, err = io.Copy(outFile, rc)

		outFile.Close()
		rc.Close()

		if err != nil {
			return filenames, err
		}
	}

	return filenames, nil
}

// DownloadFile Downloads a file through http
func DownloadFile(filepath string, url string) error {
	resp, err := http.Get(url)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	out, err := os.Create(filepath)
	if err != nil {
		return err
	}
	defer out.Close()

	_, err = io.Copy(out, resp.Body)
	return err
}